1. Field of the Invention
The present invention relates to current measurement apparatuses which measure the magnitude of a current which is to be detected and which flows through a conductor, and particularly to a current measurement apparatus which detects the magnitude of a current to be detected, via a change in magnetic resistance.
2. Description of the Related Art
Recently, in the field of, for example, electric cars or solar batteries, as electric cars or solar batteries have come to be of higher power and higher performance, a current value used therein has become larger. Accordingly, current sensors that measure a large direct current in a noncontact manner have been widely used. As one of such current sensors, a current sensor has been proposed which includes Hall elements that detect the magnitude of a current flowing through a conductor, via a magnetic field that occurs around the conductor (for example, see Japanese Unexamined Patent Application Publication No. 2007-107972).
This current sensor includes a semiconductor substrate having an opening, and multiple Hall elements that are disposed on the semiconductor substrate and that output Hall voltage signals on the basis of a change in a magnetic field. A current line through which a current to be detected flows is disposed orthogonally to the semiconductor substrate so as to pass through the opening of the semiconductor substrate. The Hall elements are disposed in a circle, the center of which is located on the current line. The current sensor described in Japanese Unexamined Patent Application Publication No. 2007-107972 detects the magnitude of a current to be detected, by using the Hall voltage signals that are output from the Hall elements on the basis of a change in a magnetic field which occurs around the current line when the current to be detected flows through the current line.